Fifteen kids in New York City have been hospitalized with a rare, life-threatening inflammatory syndrome “potentially associated with COVID-19,” health officials said in an alert Monday night.

Four of the 15 children with suspected Kawasaki disease also tested positive for the coronavirus, the city’s Health Department said.

Six others tested positive for having COVID-fighting antibodies.

Kawasaki disease is a rare childhood illness that causes the walls of blood vessels in the body to become inflamed. Symptoms include high temperature that lasts for five days or longer, redness in the eyes, rashes and swollen glands in the neck.

Children younger than 5 are most at risk.

“If the above-described inflammatory syndrome is suspected, pediatricians should immediately refer patients to a specialist in pediatric infectious disease, rheumatology, and/or critical care, as indicated,” Dr. Demetre Daskalakis, deputy city health commissioner for disease control, said in the memo to health care providers.

“Early diagnosis and treatment of patients meeting full or partial criteria for Kawasaki disease is critical to preventing end-organ damage and other long-term complications,” he added.

Some patients also require intensive care for heart and respiratory problems, Daskalakis said.

Links between COVID-19 and Kawasaki syndrome has also sparked concerns in the UK and Italy and the World Health organization is investigating whether there is a connection between the killer bug and inflammatory syndrome.

The 15 kids in the city were hospitalized between April 17 and May 1.

Five of the children required mechanical ventilation but no fatalities have been reported thus far.